1. Field of the Invention
The present invention relates, in general, to lifts having vertical columns in which lift arms are supported in cantilever fashion therefrom and which lift arms in turn act as supports for vehicles in service stations, repair centers and the like to lift such vehicles for the repair and servicing thereof.
2. Information Disclosure Statement
Heretofore, such lifts for each of the columns have typically utilized a single channel or a pair of channels inwardly opening towards one another with each of the columns being supported at the lower end thereof on a supporting surface and extending vertically upwardly from the supporting surface. In each of the columns follower means in the form of either one or more rollers or one or more blocks move in the channels. The follower means are operatively connected to one or more lift arms to hold the arm(s) in cantilever fashion relative to the column as the lift arm(s) is/are moved upwardly, downwardly or is/are held in any given position. Also, typically the rollers or blocks are in pairs, i.e., an upper pair and a lower pair. The lower rollers or blocks roll or slide against the web or back of the channel and the upper rollers or blocks load the flanges of the channel with an outward pulling or shear force against the flanges in a direction away from the web of the channel tending to bend the flanges outwardly and cause problems such as the outward bulging of the flanges with the eventual possibility of the rollers or blocks pulling out of the channel causing the lift arm to fall. Thus, a dangerous situation could occur with the consequent injury to personnel and damage to the vehicle.
After the present invention was conceived by me, it was brought to my attention that in another field, i.e., the conveyor field, a configuration for the tracks for trolleys in overhead conveyors was in existence somewhat similar to the column configuration of the columns in my invention. However, I do not believe that it is an analogous art. Further, I do not believe that a person skilled in the vehicle lift field would look to the conveyor field for suggestions, and the problems are different in the two fields. Thus, in the field of the present invention the vehicle lifts utilize a cantilever effect on a vertical column supported vertically only at the base thereof with the shear forces acting on the column in a horizontal direction, with the forces acting on the upper set of rollers or blocks tending to pull the column in one direction and the forces acting on the lower set of rollers pushing in the opposite direction. In contrast, in an overhead trolley system the track is held horizontal at spaced points along the length thereof and the forces are vertical forces from the trolley acting downwardly on the track. Also, in the conveyor field there is no concern about any upward force acting against the web of the track, whereas in the vehicle lift field the web should be flat since the lower rollers or blocks are bearing thereagainst.